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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        div {
            width: 100px;
            height: 100px;
            background-color: skyblue;
        }
    </style>
</head>

<body>
    <div>123</div>
    <a href="https://www.baidu.com">百度</a>
    <script>
        var div = document.querySelector('div');
        div.onclick = function (e) {
            console.log(e);
            console.log(e.target);//点击哪个元素就返回哪个元素
            console.log(this);//返回绑定事件的元素
        }

        var a = document.querySelector('a');
        a.addEventListener('click', function (e) {
            e.preventDefault();//阻止默认事件
        })

        //stopPropagation阻止冒泡
    </script>
</body>

</html>